Bartonella Species

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • High level of suspicion based on symptoms and exposure risk

Laboratory Testing

  • CDC Bartonella diagnosis and treatment information
  • Bartonella henselae
    • Nonspecific testing
      • CBC – mildly elevated white blood cell count and elevated or diminished platelets
    • Acute and convalescent serum specimens for antibody testing – 70-90% positive in immunocompetent patients
      • Best evidence of infection is significant change on two appropriately timed specimens, where both tests are performed in same laboratory at same time
      • Confirmation requires a fourfold change in titers between acute and convalescent specimens
      • Low-positive IgG – suggests past exposure or infection
      • High positive IgG – may indicate current or recent infection (but not conclusive)
    • PCR from whole blood, tissue, or cerebrospinal fluid
      • Rapid test
      • Relatively sensitive, very specific
    • Culture of involved nodes – difficult; long incubation periods with poor yield
      • Not recommended – sensitivity very low
  • Bartonella quintana
    • Trench fever – may require culture, PCR, or serology
    • Endocarditis – blood cultures may be negative


  • Warthin-Starry silver stain
    • B. henselae – pathologic examination of involved nodes
    • B. quintana – diagnosis of bacillary angiomatosis based on histopathologic findings of angiomas associated with tiny clumps of bacilli

Differential Diagnosis

Bartonella spp cause several different diseases, including cat scratch disease (CSD).


  • B. henselae
    • Incidence – 22,000 infections annually in the U.S. (~9/100,000)
    • Age – children <1 year have the greatest rate of infection
    • Occurrence – most common in warm, humid climates during autumn and winter months
    • Transmission – usually by cats to humans (fleas mainly transmit the disease directly through a cat scratch; flea-borne transmission to humans may also occur)
      • Most affected patients do not recall being scratched by a cat
  • B. quintana
    • Incidence – generally low; however, increasing prevalence in homeless populations in U.S. and Europe
    • Transmission – body louse (Pediculus humanus corporis)


  • Genus Bartonella contains aerobic, fastidious, gram-negative bacillus
  • Associated with four primary clinical syndromes
    • CSD – B. henselae and B. clarridgeiae
    • Bacillary angiomatosis – B. quintana and B. henselae
    • Bacillary peliosis hepatitis – B. henselae
    • Relapsing fever with bacteremia (trench fever) – B. quintana

Risk Factors

  • B. henselae
    • Cats with fleas – ~60% of strays and 40% of domestic cats are bacteremic for B. henselae
    • Rough play with cats – especially kittens
    • Unwashed bites and scratches from cats or allowing cats to lick open wounds
  • B. quintana
    • Immunocompromised persons – especially those with HIV
    • Homelessness
    • Alcoholism

Clinical Presentation

  • B. henselae
    • Immunocompetent host
      • Common presentations – CSD
        • Localized papule progressing to a pustule develops 3-5 days after cat scratch
          • Initial lesion heals uneventfully
        • Tender, unilateral regional lymphadenopathy develops 1-2 weeks later – 90% of cases
          • Generally persists for 2 weeks to 3 months before resolving spontaneously
          • Cervical and axillary – most common
          • Secondary bacterial superinfection of involved nodes – ~10% of cases
      • Other manifestations
        • Neurologic – encephalopathy, transverse myelitis, radiculitis, cerebellon ataxia
        • Hepatitis
        • Osteomyelitis
        • Disseminated infection (endocarditis) – associated with mortality
        • May also present as granulomatous disease
        • Ophthalmic
          • Conjunctival inoculation may cause Parinaud oculoglandular syndrome with conjunctivitis and periauricular lymphadenopathy
          • ​Neuroretinitis
    • Immunocompromised host
      • Bacillary angiomatosis
        • Nontender, firm, red-purple colored skin lesions
          • Dissemination to organs – pseudo neoplastic vasculitis proliferation
          • Potentially fatal if not treated
      • Bacillary peliosis
        • Vasoproliferation within the liver and spleen
          • Blood-filled cysts with possible organisms in the cysts
  • B. quintana
    • Trench fever
      • Sudden onset headache, meningitis, relapsing fever
      • Relapsing fever with bacteremia
        • Relapses common when short-course antibiotics are used
      • May cause endocarditis
      • No fatalities reported
    • Bacillary angiomatosis
      • Most common in immunocompromised patients (eg, HIV)
      • Many organs may be affected –  bone marrow, lymph nodes, liver, spleen
      • Hallmark symptoms – vascular nodules, papules, or tumors with proliferation of new blood vessels (angiogenesis)
      • Lesions, termed epithelioid angiomatosis, resembles Kaposi sarcoma
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Bartonella henselae & B. quintana Antibodies, IgG & IgM 2002280
Method: Semi-Quantitative Indirect Fluorescent Antibody


Antibodies take up to 10 days to develop

While IgM antibodies suggest recent infection, low levels may occasionally persist >12 months postinfection


If test results are equivocal, repeat testing in 10-14 days

Bartonella Species by PCR 0093057
Method: Qualitative Polymerase Chain Reaction


Negative result does not rule out the presence of Bartonella spp DNA in quantities below the sensitivity of assay or the possibility of PCR inhibitors in samples

Unidentified sequence variations may lead to a false-negative result

Bartonella Species by PCR, Whole Blood (INACTIVE as of 05/15/17: Refer to 0093057) 0060762
Method: Qualitative Polymerase Chain Reaction


Negative result does not rule out the presence of Bartonella spp DNA in quantities below the sensitivity of assay or the possibility of PCR inhibitors in samples

Unidentified sequence variations may lead to a false-negative result

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification


Less sensitive than PCR

Limited to the University of Utah Health Sciences Center only

General References

Badiaga S, Brouqui P. Human louse-transmitted infectious diseases. Clin Microbiol Infect. 2012; 18(4): 332-7. PubMed

Bartonella Infection (Cat Scratch Disease, Trench Fever, and Carrión’s Disease). Centers for Disease Control and Prevention. Atlanta, GA [Last updated Mar 2016; Accessed: Jan 2017]

Bitam I, Dittmar K, Parola P, Whiting MF, Raoult D. Fleas and flea-borne diseases. Int J Infect Dis. 2010; 14(8): e667-76. PubMed

Florin TA, Zaoutis TE, Zaoutis LB. Beyond cat scratch disease: widening spectrum of Bartonella henselae infection. Pediatrics. 2008; 121(5): e1413-25. PubMed

Kaiser PO, Riess T, O'Rourke F, Linke D, Kempf VA. Bartonella spp.: throwing light on uncommon human infections. Int J Med Microbiol. 2011; 301(1): 7-15. PubMed

McElroy KM, Blagburn BL, Breitschwerdt EB, Mead PS, McQuiston JH. Flea-associated zoonotic diseases of cats in the USA: bartonellosis, flea-borne rickettsioses, and plague. Trends Parasitol. 2010; 26(4): 197-204. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology®

Litwin CM, Johnson JM. Identification, cloning, and expression of the CAMP-like factor autotransporter gene (cfa) of Bartonella henselae. Infect Immun. 2005; 73(7): 4205-13. PubMed

Litwin CM, Rawlins ML, Swenson EM. Characterization of an immunogenic outer membrane autotransporter protein, Arp, of Bartonella henselae. Infect Immun. 2007; 75(11): 5255-63. PubMed

Medical Reviewers

Last Update: March 2017